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UNITED STATES PATENT oEEioE.

NATHAN SARGENT, OF CHARLESTOIVN, MASSACHUSETTS.

TOP FOR TABLES.

Speccaton of Letters Patent No. 25,529, dated September 20, 1859.

To all whom it may concern:

Be it known that I, NATI-IAN SARGENT, of Charlestown, in the county of Middlesex and State of Massachusetts, have invented a new and useful Improvement in Tables or Table-Tops; and I do hereby declare that the same is fully described and represented in the following specification and the accompanying drawings, of which- Figure l, denotes a top view of such table top. Fig. 2, an underside view. Fig. 3, represents the panoramic cloth, as developed 011 a plane surface. Figs. 4, and 5, denote respectively a horizontal and transverse section of the regulator or cani shaped case and its spring, to be hereinafter described.

The nature of my invention consists in a peculiar construction of the top of a table, and the application of a canvas or panoramic cloth thereto, whereby such top may be caused to appear as having either a plain or variegated surface, or as provided with a back-gammon or chess board as circumstances may require.

It also consists in a. peculiar mechanism, whereby the canvas or panoramic cloth is maintained with an equal or proper degree of tension upon each of the rollers, however such cloth may vary in thickness or in folds upon such rollers.

In the drawings, A, denotes a circular board or plate as constituting the top surface of a table, the same having a rectangular passage or hole cut through it for the reception of a plate, B, of glass or if preferable the said top plate may be made entirely of glass or other transparent material. To the underside of the said plate, A, two rollers, C, D, are disposed, the same having their journals supported in ears or projections, a, a, b, extending downward from said plate and attached thereto by screws or in any other suitable manner. To each of the said rollers, one end of the panoramicmcloth, E, is firmly atached by means of paste or glue, or in any other proper manner. One journal, c, or CZ, of each roller, C, or D, extends some distance through its bearing, and has a disk of somewhat greater diameter than the journal, as seen in Fig. 2, aflixed to its outer end; such extensions of the said journals constituting drums or windlasses, to which cords, 0, n, are afiixed, and around which they are wound or unvvound, one rope being attached to the inner end of one drum, and the other rope to the outer end of the other drum as seen in the drawings, the other end of each of the said ropes being respectively affixed to the periphery of the spring case, f, to be described. For the purpose of maintaining a uniformity of tension on each of the rollers, however much the number or folds of cloth or canvas around the same may vary, and to prevent the cords, 0, n, from overriding each other as they are either' wound upon or unwound from the drums, c, (l, I attach to the underside of a supporting board or plate, Gr, and midway between the ends of the rollers C, D, as seen in Fig. 2, an eccentric or cam case, H. This hollow case I construct of two parts or halves, e, f, and by means of a washer and key, confine them together upon a stationary arbor, L, secured to, and extending vertically from the plate, G, as seen in Fig. 2. To the inner surface of the upper half, e, of the said case, I attach or solder a hollow arbor, whose length is equal to the width of both halves of the casesuch arbor resting and turning upon a washer placed upon the inner end of the stationary arbor-the lower half of the case revolving on the hollow arbor, while the upper half revolves upon the stationary arbor. IVithin this case, a coiled spring, I, is placed, one end of which is attached to the inner' periphery of the upper half, e, while its other end is aflixed to the hollow arbor attached to the lower half, as seen in Fig. Lland furthermore, there is applied to the lower part of said case a projection or device, g, by which the case may be put in revolution, either in one direction or the other, as circumstances may require. By inspection of Fig. 2, it will be perceived that the said case has on the periphery of each of its parts, one plane surface, z', such surface being intended to be in, or nearly in the same line with the inner plane of the drums, c, (Z, when the cords, 0, a, are respectively wound upon or unwound from the drums, c, d; it will also be perceived that the leverage here exerted on the cords, 0, n, is the least, and also that as the case is revolved, the leverage or radius of the case increases, until such case has made one entire revolution; the difference between the shortest leverage and the longest, being just equal to the length of either drum or wind` lass, c, fl, and also it will be evident that this leverage increases and decreases just in proportion as the winds or coils on each drum increases and decreases. Each cord,

o, n, is fastened to or passes around the half l will wind it around one drum and unwind 20 of the case to which it is attached in a direction opposite to that of the other, so that while one cord is winding around one drum, the other cord is unwinding :from the other. The object of making the boX or case in two halves, is, that each may be capable of being revolved independently of the other, and in an opposite direction therefrom.

From the above it will be seen that as the coiled spring is attached at one end to the y hollow arbor, or one half of the case, and

the other end to the periphery of the other half, when such spring is put in revolution, such force will act with a like power upon both halves of the case, and as the cords, 0, n, are carried around the two halves in opposite directions, the revolution of the upper half, either in one direction or the other,

it from the other.

Having described my invention, what I claim, is as follows:

l. I claim as an improved article of manufacture, a panoramic table, or table top, the same being constructed and operated in manner and for the purpose specified.

2. I also claim the peculiar mechanism herein described, whereby the canvas or panoramic cloth is maintained with proper tension upon each of the rollers, however such cloth may vary in thickness or in number of folds upon such rollers.

NATHAN SARGENT.

Vitnesses:

F. P. HALE, Jr., ARTHUR NEILL. 

